Is the husband obligated to fulfill the agreement made with his wife's mother before marriage, which stipulates that the wife stays for ten days every twenty days in her mother's house, especially since the husband cannot bear her absence for that period, and is the wife sinful if she leaves the marital home and goes to her mother's house?

The husband is not required to give his wife permission to go to her family's home for the period agreed upon with her mother. It is not permissible for the wife to go without her husband's consent, and she sins by disobeying him. The fundamental principle is that it is not permissible for the wife to leave her home without her husband's permission, and her obedience to her husband takes precedence over her obedience to her parents. If there was a condition in the marriage contract regarding this, it is invalid because it contradicts the essence of the contract, as mentioned by Ibn Qudamah.